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Politics : Bill Clinton Scandal - SANITY CHECK -- Ignore unavailable to you. Want to Upgrade?

To: jbe who wrote (15451)	11/20/1998 9:02:00 PM
From: Jacques Chitte	Read Replies (2) \| Respond to of 67261

My reasons for disliking electric cars are several. 1) and most important: The promise of efficiency is hollow. We get our power from burning fossil carbon. If we do it directly in a Camry or indirectly in one of the two commercial electrics - the carbon burden is about the same. We would need nuke power - fusion and/or fission - to upset that equation. 2) and a close second to the above: Energy density is a problem. Those batt packs are big and heavy. Like a thousand pounds. And the energy they hold is marginally more than that extractable from five liters of liquid fuel. 3) That low energy density is expensive. Lead-acid cycle life is short, and hydride batteries are pricey. For the money, a piston engine waay outlasts a battery pack. Let alone the motors... 4) For all that, you get a realistic one-way range of seventy miles. Flat running, no Tahoe trips. An electric semi truck is not in the cards. 5) The current electrics are subcompact coupes (although the Honda is styled like a minimal sport-ute with that underbody batt pack) useful for two people and a small amount of gear. An electric van is impractical - except for special short-trip apps in environmentally fragile areas. Tourism, maybe - but not soccer mom duty. Of all these - I think energy density is the one insurmountable hurdle. You simply can't beat liquid hydrocarbon as a dense, stable, safe way to store kilowatt hours. Converting that hydrocarbon energy is done pretty well (in terms of thermodynamic efficiency) with piston engines. When a company really tries, remarkable efficiencies with serviceable (read: cheap to own) technology are possible. The benchmarks are my late lamented Honda Civic VX (gasoline) and some of the new direct-injection Vee Dubs (Diesel). Fifty-plus mpg in a real-life use cycle, with great reliability and low operating cost. (If you didn't get air conditioning.) In my starry-eyed [foamy-eyed?] opinion the two major missing link is a) Diesel cleanliness technology (re emissions, see prev. reverie) and b) a carbon recycle. This would be realized by agricultural Diesel production from vegetable oils. (I would stipulate that the projected biodiesel crop plant would grow well without irrigation or mineral fertilizer. We can do it now with oilseeds, but they are crops which really chomp the water and fertilizer. No point soiling the environment in order to save it... :-D) But I think that these are technical increments - easily realizable using current science as a start. The other way to use hydrocarbon energy in a vehicle would be direct conversion to onboard electricity. Fuel cells. Current fuel cells are reasonably efficient if fed molecular hydrogen. But H2 is really, really bad in the energy density department. Compressed or liquefied - its density is less than a tenth that of gasolone or diesel. And the fire hazard is made worse [than traditional fuels] by H2's broad band of explosive mixes with air and by its ability to be ignited catalytically. (Like off of platinum jewelry. Whoops!) The current crop of experimental fuel cells use hydrocarbon as a hydrogen carrier. The carbon is thrown away as waste heat, LOTs of it, and CO2. Lower efficiency than a good piston engine. A fuel cell which uses both carbon and hydrogen with air for power can be imagined. But it is my semi-informed opinion that realizing it would require a leap in technology. Not an increment from known science, but real lateral stuff. Star Trek science. Even then - I can't imagine it being cheap enough to thrive. So to summarize - from a pure engineering perspective I see the future of internal combustion [for personal and commercial transport needs] as being quite bright. Electrics are riding a wave of really good PR for now. But I wouldn't bet on that lasting as the true economies of electric vs. direct combustion are put on fair trial - once artificial subsidies have run their course. Electric city transit vehicles are an exception. What makes them workable is that electricity is not generated onboard, but drawn off the track or overhead wires. This is important, because efficient generators are HEAVY, while efficient motors are quite compact. One big generator attached to the grid can also operate continuously in its narrow peak efficiency load... yada yada yada...